I’m amazed that people start riding on full-sus, but I geuss the prices are such nowadays that most people will think ‘why not?’. Truth is that you’ll develop trail skills on a hardtail, which will make you ride much better when you upgrade to FS.
I’ve swapped between the two over the last 10yrs. I ride faster on FS, but have just as much fun on a HT.
Conversely, riding FS for a while will make you a better HT rider too – I find it makes me more confident at speed, and you look at the terrain differently. I’m currently HT only as they need less looking after.